let numbers: Set = [1, 2, 3, 4, 5]
let doubleNumbers = numbers.map { $0 * 2 }
print(doubleNumbers)  // 输出: [2, 4, 6, 8, 10]

let numbers2: Set = [1, 2, 3, 4, 5]
let evenNumbers = numbers2.filter { $0 % 2 == 0 }
print(evenNumbers)  // 输出: [2, 4]
